1. Field of the Invention
The present invention relates to apparatuses and methods for outputting image data. In particular, the invention relates to an image data outputting apparatus and an image data outputting method for outputting image data again, which has once been output and stored in the apparatus, by a simple control method while ensuring confidentiality.
2. Description of the Related Art
Examples of the image data outputting apparatus include a printer which outputs image data taken in by a scanner and the like as an image, as well as a facsimile device which outputs taken image data directly to another device.
There is also a printing system for multiple purposes as one of conventional image data outputting apparatuses. The conventional printing system stores image data in a memory such as hard disk and DRAM (dynamic random access memory) and then performs image processing on the image data to be printed out. The image data is stored in the memory by taking in the image data from any resource such as image scanner and personal computer and writing the image data in a hard disk and thereafter writing it in a DRAM, or directly writing the image data in the DRAM. After image processing on the image data read from the DRAM, the image data is output through printing out or transmission of the image data to another device such as facsimile.
Some conventional image data outputting apparatus has memory recall function. The memory recall function allows image data, which was once output and held in a DRAM or hard disk, to be read from the memory and output according to a request by an operator to output the image data again. For such an image data outputting apparatus, various studies have been done in order to achieve re-output of stored image data following a request by a particular person only, i.e., to maintain confidentiality.
Detailed description is given below concerning conventional image data outputting apparatuses which have the function of ensuring confidentiality.
A first example of such image data outputting apparatuses is an image forming apparatus disclosed in U.S. Pat. No. 5,726,770. When this image forming apparatus reads an image, a personal identification number can be input. Then, image data and a print mode concerning this image are stored together with the personal identification number. By input of the personal identification number, the image data stored together with the personal identification number and the print mode can be output at any arbitrary time in accordance with the stored print mode.
The above image forming apparatus outputs image data on condition that a personal identification number is entered. Therefore, the stored image data is never output freely by any third person. In other words, confidentiality of the stored image data can be protected.
However, this image forming apparatus requires input of a personal identification number each time image data is to be output, and thus has a problem of significantly poor operability especially when an image which was read at an immediately preceding time should be printed out repeatedly, for example, when an image is to be printed out after a trial printing.
A second example is an image forming apparatus disclosed in Japanese Patent Laying-Open No. 7-221949. This image forming apparatus has a human body detection sensor to control image data such that stored image data is erased in response to a non-sensing signal from the human body detection sensor.
A third example is an image forming apparatus disclosed in Japanese Patent Laying-Open No. 9-284518. This image forming apparatus erases stored image data according to execution of a predetermined operation or when a predetermined time has passed from execution of a copying operation.
The respective image forming apparatuses mentioned above as the second and third examples of conventional apparatuses erase stored image data in order to prevent the image data from being output freely by a third person. In other words, confidentiality of the stored image data can be preserved.
These image forming apparatuses, however, have a problem of poor usability since image data is erased and accordingly a certain operation to store the image data is required, when the erased image data should be output again.
The conventional image data outputting apparatuses have thus a problem of poor operability and usability in terms of guarantee of confidentiality of stored image data.